1. Field of the Invention
The invention proceeds from a process for eliminating or reducing at least one harmonic of a static converter and/or resonance oscillations according to the preamble of patent claim 1, as well as from a device for carrying out the process according to the preamble of patent claims 8 and 9.
2. Discussion of Background
In the respective preamble, the invention relates to a prior art disclosed in EP-A2-0,296,840. For the drive of an induction motor, that document specifies a process and a device in which undesired harmonics of a resonant circuit consisting of the induction motor and a capacitor bank connected in parallel thereto are damped. When the motor is being run up, it is particularly the 5th, 7th, 11th and 13th harmonic which cause interference. The motor is fed from the inverter of a converter with a d.c. intermediate circuit. Damping of the harmonics is performed by additional timing signals at prescribable angular distances with respect to the elementary timing signal of the thyristors of the inverter.
A disadvantage of this arrangement is that the thyristors have to be operated with an increased elementary frequency.